#include "my_stdio.h"
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>

#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
mFILE *mfopen(const char *filename, const char *mode)
{
    int fd = -1;
    if (strcmp(mode, "r") == 0)
    {
        fd = open(filename, O_RDONLY);
    }
    else if (strcmp(mode, "w") == 0)
    {
        fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0666);
    }
    else if (strcmp(mode, "a") == 0)
    {
        fd = open(filename, O_CREAT | O_WRONLY | O_APPEND, 0666);
    }
    if (fd < 0)
        return NULL;
    mFILE *mf = (mFILE *)malloc(sizeof(mFILE));
    if (!mf)
    {
        close(fd);
        return NULL;
    }
    mf->fileno = fd;
    mf->flag = FLUSH_LINE;
    mf->size = 0;
    mf->cap = SIZE;
    return mf;
}
void mfflush(mFILE *stream)
{
    if (stream->size > 0)
    {
        // 写到内核⽂件的⽂件缓冲区中!
        write(stream->fileno, stream->outbuffer, stream->size);
        // 刷新到外设
        fsync(stream->fileno);
        stream->size = 0;
    }
}
int mfwrite(const void *ptr, int num, mFILE *stream)
{
    // 1. 拷⻉
    memcpy(stream->outbuffer + stream->size, ptr, num);
    stream->size += num;
    // 2. 检测是否要刷新
    if (stream->flag == FLUSH_LINE && stream->size > 0 && stream -> outbuffer[stream->size - 1] == '\n')
    {
        mfflush(stream);
    }
    return num;
}
void mfclose(mFILE *stream)
{
    if (stream->size > 0)
    {
        mfflush(stream);
    }
    close(stream->fileno);
}